A new slip has been discovered on State Highway 1 south of Kaikōura, closing the road until several thousand cubic metres of material can be removed.
The Transport Agency said it could take at least two days to clear the slip, which is the site of previous slips.
The inland road to Kaikōura, Route 70 via Waiau and Mt Lyford, is still open.
When the slip has been cleared, the state highway to the south of Kaikōura will only be open between 7am and 6pm.